1. Field of the Invention
The invention relates to a continuously variable transmission, and more specifically to a continuously variable transmission in which speed change is performed by changing the width of a variable speed pulley.
2. Description of the Related Art
A continuously variable transmission is disclosed, for example, in Japanese Patent Application Publication No. 2006-64008 (JP-A-2006-64008), Japanese Patent Application Publication No. 2006-300270 (JP-A-2006-300270), and Japanese Patent Application Publication No. 2007-192375 (JP-A-2007-192375).
JP-A-2006-64008 discloses an example of a belt-type continuously variable transmission structure. JP-A-2006-300270 discloses a valve that inhibits the discharge of a working oil.
JP-A-2007-192375 also discloses a valve that inhibits the discharge of a working oil. However, the problem associated with the configurations disclosed in JP-A-2006-64008, JP-A-2006-300270, and JP-A-2007-192375 is that a sliding member inclines and stable rotation is difficult to ensure when the pressure inside a hydraulic chamber is decreased.